UN Secretary General Antonio Guterres has underlined the necessity for key players to hold “serious” talks on North Korea’s nuclear crisis following a thaw in relations between the two Koreas.

“Our objective remains the peaceful denuclearization of the Korean Peninsula,” Guterres told reporters at the UN headquarters on Friday.

“For that, it is absolutely essential that serious discussion take place among the key actors in this process and the UN will do everything possible to encourage them in that regard,” he added.

Guterres pointed to the unanimity of the UN Security Council members to slap sanctions against Pyongyang, saying the unified position “has created the conditions” for addressing the North Korean nuclear threat “through diplomatic engagement.”

In December 2017, the Security Council imposed a new round of US-engineered economic sanctions against Pyongyang in an attempt to cut off revenue to its military program.

The UN chief is scheduled to visit South Korea next week to hold talks with leaders in Seoul and also attend the opening ceremony of the Winter Olympic Games in Pyeongchang.

Guterres Spokesman Stephane Dujarric has not ruled out the possibility of a meeting between the UN chief and a North Korean official during the visit.

The two Koreas have long had strained ties. Tensions skyrocketed last year with repeated North Korean missile and nuclear tests and increased South Korean joint military action with the United States.

But South and North Koreas then launched rare talks in early January this year to bring North Koreans to the Pyeongchang Games after the North’s leader, Kim Jong-un, expressed his willingness to open up discussions with Seoul during his New Year speech.

Members of a North Korean delegation of 32 people, including 10 athletes of the North Korean Olympic team, arrive at the Athletes’ Olympic Village in Gangneung on February 1, 2018 to take part at the Pyeongchang Winter Olympic Games. (AFP photo)

Pyongyang agreed to send athletes, cheerleaders, officials, and an art troupe to the South, and both sides decided to march together under a unification flag at the opening ceremony and form a joint women’s ice hockey team.

The last time South Korea hosted an Olympics — in 1988 — Pyongyang refused to participate. Seoul now prepares to host its second Games, with the participation of the North, which has raised the prospect of uniting the Korean Peninsula..

Meanwhile, the North is still concerned about the prospect of US military presence in the Korean Peninsula.

Earlier on Friday, North Korea warned against plans by the United States to resume joint war games with South Korea after the Winter Olympics, insisting in an official letter to the UN that it will not “sit idle” in response.

Washington and Seoul earlier agreed to delay their annual joint war games in the region until after South Korea hosts the Pyeongchang Winter Olympics.

The US special envoy on North Korea, Joseph Yun, had said on Thursday that all options remained on the table for resolving the crisis over the North’s weapons program and that he did not believe Washington was about to provoke military action.